It is worth noting that many of the Mill features are also a "lie" (for example, the belt is still just registers and register renaming). Its just that the Mill uses lies designed for modern processor technology.
Indeed that's what the #1 paragraph at https://millcomputing.com/docs/belt/ says: "A large fraction of the power budget of modern superscalar CPUs is devoted to renaming registers: the CPU must track the dataflow of the executing program, assign physical registers and map them to the logical registers of the program, schedule operations when arguments are available, restore visible state in the event of an exception—all while avoiding register update hazards."
Here is a talk from one of the designers explaining how it is done: https://www.youtube.com/watch?v=QGw-cy0ylCc&feature=youtu.be...